Muscles of the Pectoral and Scapular Region

Question 1

Pectoralis Major

Answer 1

O: clavicular head- clavicle; sternocostal head- sup. 6 costal cartilages and sternum

I: intertubercular groove

A: A44 and int. rotation of humerus; clavicular head flexes humerus, sternocostal head extends it

N: clavicular head- lat. pectoral n. (C5, C6); sternocostal head- med. pectoral n (C7, C8, T1)

Question 2

Pectoralis Minor

Answer 2

O: ribs 3-5 near costal cartilage

I: coracoid process of scapula

A: stabilizes scapula by pulling it anteriorly and inferiorly against the thoracic wall; minor protraction

N: medial pectoral n. (C8, T1)

Question 3

Subclavius

Answer 3

O: junction of rib 1 and costal cartilage

I: clavicle

A: draws clavicle medially

N: nerve to subclavius (C5, C6)

Question 4

Serratus Anterior

Answer 4

O: lat. ribs 1-8 and fascia over intercostal muscles

I: ant. surface of medial border of scapula

A: protracts scapula; holds against thoracic wall; rotates scapula (by pulling on inf. angle of scapula)

N: long thoracic n. (C5, C6, C7)

Question 5

Deltoid

Answer 5

O: clavicle; acromion and spine of scapula

I: deltoid tuberosity of humerus

A: ant- flexion/med rotation of arm; mid-a24 of arm; post- extension/lat rotation of arm

N: axillary n. (C5, C6)

Question 6

Supraspinatus

Answer 6

O: supraspinous fossa of scapula

I: greater tubercle of the humerus

A: a24 of arm (assists deltoid); rotator cuff muscle

N: suprascapular n. (C4, C5, C6)

Question 7

Infraspinatus

Answer 7

O: infraspinous fossa of scapula

I: greater tubercle of humerus

A: lat rotation of arm; rotator cuff muscle- helps hold head of humerus in glenoid cavity

N: suprascapular n. (C5, C6)

Question 8

Teres minor

Answer 8

O: sup. part of lat. border of scapula

I: greater tubercle of humerus

A: lat. rotation of arm; rotator cuff muscle- helps hold head of humerus in glenoid

N: axillary n. (C5, C6)

Question 9

Teres Major

Answer 9

O: Dorsal surface of inf. angle of scapula

I: intertubercular groove of humerus

A: adduction and medial rotation of arm

N: lower subscapular n. (C5, C6, C7)

Question 10

Subscapularis

Answer 10

O: subscapular fossa

I: lesser tubercle of humerus

A: med rotation and a44 of arm; rotator cuff muscle- holds head of humerus in glenoid cavity

N: upper and lower subscapular n.(C5, C6, C7)